1. Field of the Invention
The present invention relates to a tool changer with covers configured to prevent foreign matter from getting into a turret.
2. Description of the Related Art
A tool changer is conventionally used to automatically change a tool to be mounted on the spindle of a machine tool. This tool changer is previously fitted with a plurality of necessary work tools such that the tool to be mounted on the machine tool spindle can be automatically replaced with a specified one, depending on the machining state.
As is generally known, Japanese Patent Application Laid-Open No. 2010-99766 discloses such an automatic tool changer for automatically changing a tool. This tool changer comprises a turret provided with a plurality of grips for gripping the tool.
The automatic tool changer disclosed in Japanese Patent Application Laid-Open No. 2010-99766, mentioned above, comprises the turret fitted with a plurality of tools such that the turret can be indexed to change the tool mounted on the spindle, whereby the tool can be changed rapidly and accurately. However, the turret is connected to a turret base with a gap defined between its front side and the turret base. Therefore, chips produced during machining and a cutting fluid may possibly get into the turret through the gap.
In some cases, the turret may be provided with cover means that prevents the chips and cutting fluid from getting into the turret during workpiece machining by the machine tool. FIG. 2 shows a prior art automatic tool changer provided with cover means attached to a turret.
An automatic tool changer 2 comprises a turret 6 as a member for changing a tool 4 mounted on the distal end portion of a spindle 3 of a machine tool 1. The spindle 3 of the machine tool 1 moves vertically (in the direction of a Z-axis) as a Z-axis ball screw 10 disposed in a column 12 is rotated by a Z-axis motor 11.
The turret 6 is fitted with a front cover 61 and a rear cover 62 that eliminate adverse affects on structural parts (not shown) therein. The front and rear covers 61 and 62 serve to prevent penetration of the chips and cutting fluid from the front and rear sides, respectively, of the turret 6.
In changing the tool 4, the Z-axis motor 11 is driven to move the spindle 3 vertically. Since the spindle 3 is provided with a cam 7, the turret 6 is swung by a cam follower 8 that follows the cam 7 as the spindle 3 is moved vertically.
Depending on the shape of the rear cover 62, chips and the cutting fluid may easily accumulate on an upper part (corresponding to region A of FIG. 2) of a cylindrical portion 64 of the rear cover 62. As the turret 6 is swung in the aforesaid manner, in this case, chips and the cutting fluid deposited on the upper part (regions A) of the cylindrical portion 64 of the rear cover 62 flow in the direction indicated by arrow B in FIG. 2, and inevitably get into the turret 6 through a gap 65 between the front and rear covers 61 and 62. Consequently, the structural parts in the turret 6 may be adversely affected.